Shrub rose plant named &#39;Sprothrive&#39;

ABSTRACT

A new and distinct variety of landscape shrub rose plant is provided which forms in abundance on a substantially continuous basis attractive semi-double blossoms that are dark bright red in coloration. The vegetation is vigorous and the growth habit is round and bushy. Attractive ornamental glossy dark green foliage is formed. Superior disease resistance to blackspot is exhibited. Additionally, the new variety is particularly well suited for growing as distinctive ornamentation in the landscape.

BOTANICAL/COMMERCIAL CLASSIFICATION

Rosa hybrida/Shrub Rose Plant

VARIETAL DENOMINATION

cv. Sprothrive

SUMMARY OF THE INVENTION

The new variety of landscape shrub rose plant of the present inventionwas created by artificial pollination carried out at Bakersfield,Calif., U.S.A., wherein two parents were crossed which previously hadbeen studied in the hope that they would contribute the desiredcharacteristics. The female parent (i.e., the seed parent) was theproduct of the cross of the ‘Meimonblan’ variety (U.S. Plant Pat. No.12,579) and the ‘Scrivluv’ variety (non-patented in the United States).The ‘Scrivluv’ variety sometimes is known as the ‘Baby Love’ variety.The male parent (i.e., the pollen parent) of the new variety was the‘Wekcisbako’ variety (U.S. Plant Pat. No. 18,552). The ‘Wekcisbako’ maleparent incorporated the ‘Radrazz’ variety (U.S. Plant Pat. No. 11,836)as its male parent. The parentage of the present invention can besummarized as follows:

(‘Meimonblan’×‘Scrivluv’)×‘Wekcisbako’.

The seeds resulting from the above pollination were sown and smallplants were obtained which were physically and biologically differentfrom each other. Selective study resulted in the identification of asingle plant of the new variety.

It was found that the new variety of landscape shrub rose plant of thepresent invention possesses the following combination ofcharacteristics:

-   -   (a) abundantly and substantially continuously forms attractive        semi-double blossoms that are dark bright red in coloration,    -   (b) exhibits a round and bushy growth habit,    -   (c) forms vigorous vegetation,    -   (d) forms attractive ornamental dark green foliage with a glossy        finish, and    -   (e) exhibits superior resistance to blackspot.

A new rose variety is provided having attractive dark bright red blooms,combined with substantially continuous blooming and blackspotresistance. The blossom coloration approaches that of fire engine red.

The new variety well meets the needs of the horticultural industry. Itcan be grown to advantage as attractive ornamentation in parks, gardens,public areas, and residential landscapes. Accordingly, it isparticularly well suited for growing in the landscape. The dark brightred blossoms contrast nicely with the glossy green foliage.

The characteristics of the new variety have been found to be homogeneousand stable and are strictly transmissible by asexual propagation atWasco, Calif., U.S.A., such as budding, grafting, and vegetativepropagation from one generation to another. Accordingly, the new varietycan be asexually reproduced in a true-to-type manner.

The new variety has been named ‘Sprothrive’, and will be marketed underthe THRIVE! trademark.

The new variety can be readily distinguished from its ancestors upon aninspection of the blossoms. More specifically, the ‘Meimonblan’ varietyforms marigold orange blossoms. The ‘Scrivluv’ variety forms deep yellowblossoms. The ‘Wekcisbako’ variety forms red blossoms having singlepetalage unlike the new variety. The ‘Radrazz’ variety forms blossoms oflighter red coloration. For instance, the dark bright red blossomcoloration of the new variety approaches that of Red Group 46A whilethat of the ‘Radrazz’ variety commonly is between Red Group 53C and RedGroup 53D of the R.H.S. Colour Chart of The Royal Horticultural Society.During observations to date, the blackspot resistance of the newvariety, while superior, has been somewhat less than that of the‘Radrazz’ variety.

BRIEF DESCRIPTION OF THE PHOTOGRAPH

The accompanying photograph shows, as nearly true as it is reasonablypossible to make the same in a color illustration of this character,typical blossoms of the new variety. The illustrated plant wasapproximately three years of age and was being grown outdoors on its ownroots in the field at West Grove, Pa., U.S.A.

DETAILED DESCRIPTION

The chart used in the identification of colors is that of The RoyalHorticultural Society (R.H.S. Colour Chart). The description is based onthe observation of three-year-old specimens of the new variety duringJune while grown outdoors on their own roots at West Grove, Pa., U.S.A.

-   Class: Landscape Shrub Rose.-   Plant: height — approximately 4-½ feet on average at the end of the    growing season.    -   -   Width.—approximately 3 feet on average at the end of the            growing season.        -   Habit.—round, and bushy.-   Branches: color — young stems: near Yellow-Green Group 144A. — adult    wood: Yellow-Green Group 144A with highlights of Greyed-Red Group    182A on areas most exposed to the sun.    -   -   Thorns.—size: approximately 1 cm in length on average. —            color. Greyed-Purple Group 183B.-   Leaves: stipules — parallel with auricle facing outward.    -   -   Petioles.—upper surface: near Green Group 137B. — under            surface: near Green Group 137A.        -   Leaflets.—number: 3, 5, and 7. — shape: ovate with a            serrulate margin, rounded base, and acuminate tip. — size:            terminal leaflets commonly are approximately 7.5 cm in            length and approximately 4.5 cm in width on average, and            lower leaflets commonly are approximately 5.5 cm in length            and approximately 3.5 cm in width on average. — texture:            smooth. — overall appearance: very dense, leathery, and dark            green in coloration, with a glossy finish. — color (adult            foliage): upper surface: commonly near Yellow Green Group            147A. under surface: commonly near Yellow-Green Group 147B.-   Inflorescence:    -   -   Number of flowers.—commonly approximately 5 blooms per stem            on average in a cluster.        -   Peduncle.—Yellow-Green Group 144A with highlights of            Greyed-Red Group 182A on areas most exposed to the sun,            approximately 6 cm in length on average and approximately 2            mm in diameter on average.        -   Sepals.—number five. — upper surface: near Yellow-Green            Group 145D, somewhat soft, and tomentose. — under surface:            near Yellow-Green Group 143A, somewhat rough in texture, and            moderately hispidulous.        -   Buds.—shape: ovoid. — length: approximately 2 cm on average.            — diameter: commonly approximately 1.5 cm on average. —            color: near Red Group 46A.        -   Flower.—form: semi-double and informal. — diameter            approximately 5.5 cm on average. — color upper surface: near            Red Group 46A and Yellow Group 4C at the point of            attachment. under surface: near Red Group 45C and Yellow            Group 4D at the point of attachment. — fragrance: none            noticeable. — petal form: wedge-shaped with a curled apex. —            petal number approximately 10 on average. — petal drop: very            good, with the petals commonly dropping cleanly and freely.            — stamen number approximately 80 to 90 on average. —            anthers: Greyed-Orange Group 163A in coloration. —            filaments: Yellow-Orange Group 17B in coloration, and            commonly approximately 5 to 10 mm in length. — pistils:            separate and free, and commonly approximately 25 in number            on average. — stigmas: Yellow-Orange Group 17C in            coloration. — styles: Red Group 41B in coloration, and            approximately 2 mm in length on average. — receptacle:            achenes stand on the bottom and wall.-   Development:    -   -   Vegetation.—vigorous and strong.        -   Blossoming.—abundant and substantially continuous.        -   Resistance to diseases.—superior with respect to blackspot,            rust and mildew.        -   Propensity to form hips/seeds.—spare.        -   Hardiness.—U.S.D.A. Hardiness Zone Nos. 6 to 9. The plant            has thrived in a harsh Pennsylvania, U.S.A., test field for            two years with no spraying or irrigation.

Plants of the new ‘Sprothrive’ variety have not been observed under allpossible environmental conditions to date. Accordingly, it is possiblethat the phenotypic expression may vary somewhat with changes in lightintensity and duration, cultural practices, and other environmentalconditions.

1. A new and distinct variety of landscape shrub rose plantcharacterized by the following combination of characteristics: (a)abundantly and substantially continuously forms attractive semi-doubleblossoms that are dark bright red in coloration, (b) exhibits a roundand bushy growth habit, (c) forms vigorous vegetation, (d) formsattractive ornamental dark green foliage with a glossy finish, and (e)exhibits superior resistance to blackspot; substantially as herein shownand described.